3,224 research outputs found
From vortex molecules to the Abrikosov lattice in thin mesoscopic superconducting disks
Stable vortex states are studied in large superconducting thin disks (for
numerical purposes we considered with radius R = 50 \xi). Configurations
containing more than 700 vortices were obtained using two different approaches:
the nonlinear Ginzburg-Landau (GL) theory and the London approximation. To
obtain better agreement with results from the GL theory we generalized the
London theory by including the spatial variation of the order parameter
following Clem's ansatz. We find that configurations calculated in the London
limit are also stable within the Ginzburg-Landau theory for up to ~ 230
vortices. For large values of the vorticity (typically, L > 100), the vortices
are arranged in an Abrikosov lattice in the center of the disk, which is
surrounded by at least two circular shells of vortices. A Voronoi construction
is used to identify the defects present in the ground state vortex
configurations. Such defects cluster near the edge of the disk, but for large L
also grain boundaries are found which extend up to the center of the disk.Comment: 15 pages, 10 figures, RevTex4, submitted to Phys. Rev.
Efeito das condições de extração no rendimento e qualidade do leite de castanha-do-Brasil despeliculada.
Autoria: FERBERG [i.e. FELBERG], I
Bipolar HII regions - Morphology and star formation in their vicinity - I - G319.8800.79 and G010.3200.15
Our goal is to identify bipolar HII regions and to understand their
morphology, their evolution, and the role they play in the formation of new
generations of stars. We use the Spitzer and Herschel Hi-GAL surveys to
identify bipolar HII regions. We search for their exciting star(s) and estimate
their distances using near-IR data. Dense clumps are detected using
Herschel-SPIRE data. MALT90 observations allow us to ascertain their
association with the central HII region. We identify Class 0/I YSOs using their
Spitzer and Herschel-PACS emissions. These methods will be applied to the
entire sample of candidate bipolar HII regions. This paper focuses on two
bipolar HII regions, one interesting in terms of its morphology,
G319.8800.79, and one in terms of its star formation, G010.3200.15. Their
exciting clusters are identified and their photometric distances estimated to
be 2.6 kpc and 1.75 kpc, respectively. We suggest that these regions formed in
dense and flat structures that contain filaments. They have a central ionized
region and ionized lobes perpendicular to the parental cloud. The remains of
the parental cloud appear as dense (more than 10^4 per cm^3) and cold (14-17 K)
condensations. The dust in the PDR is warm (19-25 K). Dense massive clumps are
present around the central ionized region. G010.32-00.14 is especially
remarkable because five clumps of several hundred solar masses surround the
central HII region; their peak column density is a few 10^23 per cm^2, and the
mean density in their central regions reaches several 10^5 per cm^3. Four of
them contain at least one massive YSO; these clumps also contain extended green
objects and Class II methanol masers. This morphology suggests that the
formation of a second generation of massive stars has been triggered by the
central bipolar HII region. It occurs in the compressed material of the
parental cloud.Comment: 32 pages, 28 figures, to be published in A&
Neutrinos and Nucleosynthesis in Supernova
The type II supernova is considered as a candidate site for the production of
heavy elements. The nucleosynthesis occurs in an intense neutrino flux, we
calculate the electron fraction in this environment.Comment: RevTex4 style, 3 pages including 1 figure. Presented at Mexican
School of Astrophysics 2002, Guanajuato, Mexico, 31 Jul - 7 Aug 2002. Final
version to appear in the Proceedings of IX Mexican Workshop on Particles and
Fields Physics Beyond the Standard Model, Colima Col. Mexico, November 17-22,
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Transformação de algodão (Gossypium Hirsutum L.) através do uso de policátion.
bitstream/CNPA/21492/1/CIRTEC81.pd
Carnitine partially improves oxidative stress, acrosome integrity, and reproductive competence in doxorubicin-treated rats
Doxorubicin has been largely used in anticancer therapy in adults, adolescents, and children. The efficacy of l-carnitine as an antioxidant substance has been confirmed both in humans and rats. Carnitine, present in testis and epididymis, is involved in sperm maturation. It is also effective in infertility treatment. As a continuation of a previous study, we evaluated whether some spermatic qualitative parameters, DNA integrity, chromatin structure, and fertility status, could be ameliorated by the carnitine treatment in adult rats, which were subsequently exposed to doxorubicin at pre-puberty. Pre-pubertal male rats were distributed into four groups: Sham ControlDoxorubicinl-carnitinel-carnitine+Doxorubicin (l-carnitine injected 1h before doxorubicin). At 100days of age, all groups were reassigned into two sets: One set was submitted to the evaluation of sperm motility, acrosome integrity, mitochondrial activity, sperm chromatin structure analysis (SCSA), and evaluation of the oxidative stress. The other set of rats was destined to the evaluation of reproductive competence. The percentage of spermatozoa with intact acrosome integrity was higher in the Carnitine+Doxorubicin group when compared with the Doxorubicin group. However, sperm motility and mitochondrial activity were not improved by carnitine pre-treatment. Both values of malondialdehyde and nitrite (indirect measurement of nitric oxide) concentrations were statistically higher in the only doxorubicin-treated group when compared to the Carnitine+Doxorubicin group. Fertility index and implantation rate were lower in Doxorubicin group, when compared to Carnitine+Doxorubicin group. Moreover, the percentage of spermatozoa with damaged DNA was higher in the Doxorubicin-treated group when compared to the Carnitine+Doxorubicin group. l-carnitine, when administered before doxorubicin, partially preserved the acrosome integrity, an important feature related to sperm fertilization ability that positively correlated with the reproductive competence and sperm DNA integrity at adulthood. In conclusion, l-carnitine attenuated the long-term alterations caused by doxorubicin in the germ cells and improved male reproductive capacity in adulthood.National Council for the Improvement of Higher Education (CAPES/Brazil)Fed Univ Sao Paulo UNIFESP, Lab Dev Biol, Dept Morphol & Genet, Botucatu St 740,Leitao da Cunha Bldg,2nd Floor, BR-04023900 Sao Paulo, SP, BrazilFed Univ Sao Paulo UNIFESP, Lab Dev Biol, Dept Morphol & Genet, Botucatu St 740,Leitao da Cunha Bldg,2nd Floor, BR-04023900 Sao Paulo, SP, BrazilWeb of Scienc
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